This will give you a general idea of how much it would cost line by line item for the exterior and interior.

I'm not going to bid on this specific property, but wanted to get feedback on how to evaluate capex costs for a property with no access to interior.

I also painted the interior of both units.

We are currently in the middle of complete interior renovations.

I did minimal cosmetic work to the interior and had the exterior painted.

Cured deferred maintenance (overgrown landscaping, peeling paint, tilted mailboxes), cosmetic work including interior and exterior paint, rebuild of patio fencing, striping of parking lot.

I plan to rent the house for as long as possible.I was not expecting to have the opportunity to choose the siding, gutters, roof, interior color schemes including countertops, etc.

The C class properties here all seem to list and sell for around $45,000; anything under that is likely storm damaged from Hurricane Florence from 2018 still (major flood, mold, rot, etc.) and the repair estimates would exceed the ARV of the house -- i.e. new roof, gutting entire interior, mold mitigation, new windows, new floors throughout, beautified kitchens and bathrooms (not necessarily upgraded)... in other words, the ones I've found in the $20k range usually need to be rebuilt as new houses. 

And if they have to drill holes for interior piers, you pretty much will have to replace the entire flooring. $$$$3.

An easier option might be to cut the copper and run new plumbing via interior walls and/or floor cavities, probably pex.